It has been known that silicon halides and more particularly organosilicon halides can be prepared by effecting a reaction between organic halides, especially hydrocarbon halides and a silicon component of a solid, porous contact mass containing silicon and a metallic catalyst for the reaction at elevated temperatures. However, over a period of time, the hydrocarbon halides and the hydrocarbon substituted silicon halides will pyrolyze to a certain degree at the reaction temperatures. This results in the formation of hydrocarbons and gums which gradually coat the silicon particles and bring the reaction to an end. The resultant solid porous contact mass containing up to about 40 percent by weight of inorganic substances other than elemental silicon is often referred to as a "dead bed" or "spent" residue. Generally, the "spent" residue which contains elemental silicon particles having a maximum diameter up to about 50 microns was sent to a smelting process or it was discarded.
When the "spent" residue was discarded, it would contaminate the environment and when the residue was treated by the smelting process, large amounts of energy were required. Thus, it has been found that the "spent" residue can now be reactivated and reused in the preparation of silicon halides without contaminating the environment and without expending large amounts of energy.
Therefore, it is an object of this invention to provide a process for reactivating a "spent" residue containing elemental silicon. Another object of this invention is to provide a method for reactivating a residue without having to consume large amounts of energy. A further object of this invention is to provide a method for utilizing a residue containing elemental silicon in the preparation of silicon halides.